Staffordshire Police said in a statement: "This incident has had a huge impact on the community and we understand there will be confusion and a demand for information.

"However, we would urge people not to speculate as to what may have happened and appeal for patience as the investigation continues.

"We will provide further updates as soon as we are able to."

Image:Chris Moulton and Natalie Unitt were treated in hospital with non life-threatening injuries

Photos from the scene showed part of the roof of the house collapsed, windows were smashed and the inside was blackened with smoke.

Nicola Glover is the headteacher at Castlechurch Primary School which was attended by three of the children.

She said: "Our entire school community is absolutely devastated by this news.

Image:The four children were killed in the fire on Tuesday

"Riley was a very confident, excitable member of school who came every day full of enthusiasm. He was a caring friend who hated to see anyone hurt or upset and would do his best to help or cheer them up.

"Tilly was a happy little girl who loved coming to nursery. She was a friendly and caring child who loved to read stories, dress up and paint.

"Olly was a happy, loving boy who loved cuddles. He was always happy to come to nursery and loved to be in the role play area with the dolls.

Image:Firefighters attended the scene in the early hours of Tuesday morning

"We have put in place support in school for staff and pupils, to help anyone who feels affected. Our sympathies are with the children's family and friends at this unimaginably difficult time."

Kim Ellis, headteacher at Marshlands Special School where Keegan was a pupil, said: "Keegan was lively, full of fun and mischief with a really endearing smile. He loved school and everyone who worked with him loved him. We are all so proud of him and the progress that he had made.

"It is very hard to accept what has happened. Our school community are understandably devastated and our thoughts and prayers are with his family."

Chief Inspector John Owen of Staffordshire Police described the incident as "absolutely heartbreaking".

A friend of the children's mother said she believed the family had lived at the house for around six months, having moved there from another part of Stafford.